ELGIUM tries to woo companies by offering them massive tax breaks to establish their headquarters within the country’s borders. Ireland temporarily lowered its corporate income tax rates to lure foreign manufacturing businesses and banks to its shores. Luxembourg and the Netherlands offer their own unique sweetheart deals to multinationals.

So much for a unified Europe. While businesses can benefit from countries’ competing tax rates, there is a catch. Multinationals also must endure the cost and complication of complying with the 15 European Union nations’ very different tax systems. “It makes it more difficult to achieve the proper tax result and avoid double taxation,” explained James Diller, who heads European tax planning for General Motors Corporation.